1. Field of the Invention
The present invention relates to a diathermic hand-held instrument for use in surgical procedures. With the aid of instruments of this type, cancerous tumors are surgically removed in a known manner using ultrasonic oscillations. These ultrasonic oscillations are generated in a handle region of the hand-held instrument and transmitted to the tip of a probe of the instrument which resects the cancerous tumor tissue. A rinsing agent supply line and a suction line are provided in fluid communication with the tip region of the probe and facing the operating site.
2. Related Background Art
Hand-held instruments of this type have proven useful in the surgical removal of cancerous tumors. Such hand-held instruments act as ultrasonic tissue crushers. The functioning principle is that high-frequency, longitudinal oscillations (approximately 24 Khz) are generated and transmitted through a probe by transducers disposed in the handle or proximate region of the hand-held instrument. A distal tip of the probe executes longitudinal oscillations that destroy cancer tissue, which is considerably more sensitive to mechanical stress than healthy tissue. By means of the oscillations in the region of the probe tip, tumor tissue that comes into contact with the tip is disintegrated. With the aid of a rinsing fluid supplied via a rinsing agent supply line, such disintegrated tissue is suctioned off via a suction line.
Because of damage to associated blood vessels, severe hemorrhaging can occur during this type of surgical procedure. Such hemorrhaging must be stopped as quickly as possible. Typically, hemorrhaging of this kind is stopped with the aid of additional devices, such as clamps, resistance-wire electrodes, and the like.
One example of a hand-held instrument with a built-in rinsing agent supply line and an integrated suction line is described in German Utility Patent DE-GM No. 89 14 513. However, when severe hemorrhaging occurs during operations executed with this instrument, it has been found that the above-described additional tools still are needed.
Conventionally, hemorrhaging is stopped within an open operating site by a known coagulating technique, wherein capillary vessels are welded together with the aid of a micro-electric, inert-gas welding tool. One example of a tool of this type is described in detail in German Published, Non-Examined Patent Application DE-OS 37 10 489 (equivalent to U.S. Pat. No. 4,781,175). In that tool, electrical energy is conducted in electric arcs to tissue in a living organism through which blood flows to effect electrosurgical coagulation. This tool also provides for removal of blood from the surface of a tissue by conducting a continuous laminar jet of ionizable gas. In this manner, a scab or eschar with predetermined properties is produced by conducting electrical energy in electrical arcs.
As shown in U.S. Pat. No. 4,781,175, one pen-like, hand-held instrument can be manipulated by the surgeon during the coagulation procedure. Such an instrument comprises a nozzle for generating a gas jet, and a structure including an electrode disposed in the gas jet for transmitting electrical energy, and a cord connects the hand-held instrument to both a gas supply device and to an electrical generator. The cord embodies a plurality of gas-conducting hollow chambers extending over its length and disposed around an electrical conductor. In other words, all of these chambers extend parallel to the electrical conductor.
Such a pen-like, hand-held instrument also includes a handle that is connected to the cord, a nozzle- and electrode-holding device to which the nozzle and the electrode are connected in integral fashion, and a coupling device. The coupling device is connected to the handle to allow detachable connections of the nozzle- and electrode-holding device with the hand-held instrument. In addition, the coupling device both electrically connects the electrode to the electrical conductor of the cord and also conducts gas from the gas conducting conduit into the nozzle.
Another known micro-welding device of this same type is described in German Utility Patent No. 91 04 559, which illustrates a structure simplified with respect to the tool as described in DE-OS 37 10 489.
Both known systems perform an inert gas coagulation utilizing a central electrode as the electrical conductor that is disposed in the rinsing gas current for supplying the electrical energy needed to ionize gas at the exit point of the device. Because that central electrode inside the gas current chamber is not fixed with respect to the chamber wall over substantial portions of its length, a number of distinct, undefined changes in electrode location occur during use. Further, electrode bending vibrations occur depending on the mechanical strength of the conductor. Hence, the shape of the gas current cross-section constantly changes, and this causes turbulence in the gas current.
There also is a feedback of such turbulence to the central electrode, which is capable of oscillating. The feedback intensifies such oscillations, and causes a "buildup" of turbulence which generates short-term resonances, which are noticed as singing or crackling noises and often occur with these methods. Electrical instabilities within an initiated plasma jet also may be caused by standing waves due to such resonances, and such instabilities cause a layering of the plasma into light and dark regions.
As a result of such method-related, inherent turbulences, conventional micro-welding devices have the further drawback that atmospheric oxygen will become entrained in the rinsing gas current, whereby an oxidation will take place on the tissue surface to be coagulated. Such an oxidation is intended to be avoided with the selection of an inert gas as the rinsing gas, but a discoloration of the plasma jet is a characteristic that indicates an unwanted entrainment of air.
Also, as a result of thermodynamic interactions (e.g., differences in density and temperature), generation of a plasma jet through ionization of a gas current that is initiated at its center will cause an expansion of the plasma jet. Such a jet then will attain a final effective cross-section of up to several square millimeters on the tissue surface to be coagulated. Expansion of the plasma jet is further increased by electromagnetic rotational fields formed inside the highly-ionized core region. Hence, very precise operation of the device, as demanded by microsurgery and neurosurgery, for example, is not possible.
A tubular sonotrode device, without any provision for suction line or rinsing agent function, is illustrated by MORRISON, ET AL. (U.S. Pat. No. 4,060,088).